1. Field of the Invention
The present invention relates to a boat propulsion system, and a control device and a control method for the boat propulsion system. More specifically, the present invention relates to a boat propulsion system including an electronically controlled shift mechanism, and a control device and a control method for the electronically controlled shift mechanism.
2. Description of the Related Art
There is a conventional technique to drive a shift mechanism of an outboard motor using an electric actuator to switch the shift position, as disclosed in, for example, JP-A 2006-264361. In the shift mechanism disclosed in JP-A 2006-264361, the electric actuator engages and disengages a dog clutch to make gear shifts among forward, reverse, and neutral positions.
When the boat is to be stopped, in general, a gear shift is made to a direction that is opposite to the traveling direction. Specifically, in the case where the current shift position is the forward position, a gear shift is made to the reverse position. This generates a propulsive force in the opposite direction to the traveling direction. As a result, the boat is stopped.
In the case where a gear shift is made to the opposite direction to the traveling direction, however, the rotational direction of a propeller shaft becomes opposite before and after the gear shift. Therefore, a particularly large load may be applied to a power source and a power transmission mechanism at the time of the gear shift to the opposite direction to the traveling direction. In addition, in the case where a gear shift is made first from the forward position to the neutral position and then to the forward position, a load may be applied to the power source and the power transmission mechanism.